We present the case of a 19-year-old Moroccan patient with bilateral severe optic neuropathy resistant to conventional immunomodulatory and immunosuppressive treatments. Brain MRI revealed typical multiple sclerosis (MS) lesions. Lumbar puncture revealed unmatched Oligoclonal Bands (OCB). Given red flags against a typical MS and the bilateral, sequential, and severe visual loss with no improvement of his optic neuritis, investigation for Leber's Hereditary Optic Neuropathy (LHON) was conducted and confirmed the diagnosis genetically. This case highlights the intriguing association of Leber's disease with demyelinating lesions, raising questions about a potential common pathophysiology, and discussing the added value of a maintaining treatment of MS.